Options for Washer drainage

[decarguy]

Hi, I've been perusing these many great threads and need some advice.
We have a 36 year old house with 1.5" drain pipe to a standalone laundry area. This was probably code at the time. We have a brand new LG high capacity washer and have had no problems to date. I know this is a 1.5" drain because I tore out the drywall with the idea of moving the washer and adding a laundry sink. My understanding is that the 1.5" drain is not even up to current code for a washer let alone adding a laundry sink to the drain line. Unfortunately, the drain runs under a cement slab making any attempt to upgrade to 2" pipe difficult. Below are my known options. I would like input on each of these options and any others that I may not have thought of. Thanks in advance.

1. Tear up the cement floor and replace the 1.5" with 2" drain. This would be a very last straw.

2. Add the laundry sink (with proper connections and venting) and just avoid using it while the washer is draining (this is not likely to be a big problem). This is probably what my wife would like. Since our current high capacity washer does not seem to have any problems, we could probably get away with this. I know this does not meet current code but if they had put in a laundry sink back in the day we would probably be sailing along without problems and everything would be "legal". I know that whenever you change any plumbing you should bring it up to current code so I am reluctant to do this, but...

3. Remove the washer box drain and connect the laundry sink and then drain the washer into the sink. I suppose the laundry sink gives me some "overflow capacity" that would help guard against someday exceeding the capacity of the 1.5" drain pipe (i.e. it gets partially clogged). My wife does not particularly like this idea. And, I can see where there could be a problem if the sink drain got plugged with something accidentally (sounds like something I would do). I think it would be in compliance with current code.

4. Forget about the sink and live with the 1.5 until they create washers that exceed this older plumbing.

Thanks again.

 

[Cacher_Chick]

The new washers use much less water than the old ones, so as long as the pipe is kept clear you should not have a problem. 2" is code if you are going to do a replacement of the drain line, and there should never be a drain line smaller than 2" below a slab.

 

[Sponsor]

 

[hj]

I assume this is a concrete slab floor, if so the pipe under the floor is very UNLIKELY to be 1 1/2", since it should be cast iron and the smaller size cast iron was almost never used as a drain line. Not using both items at the same time would eliminate any possible conflict.

 

[decarguy]

Yes, concrete slab floor in that part of the house. The pipe running under the slab is 1 1/2" ABS - I can see where is leaves the basement and where it comes up out of the slab. This must have met code at the time as this house was built by a highly regarded builder at the time. The house was built in 1978. Cast iron was not being used in this area then.

 

[decarguy]

What was done 30+ years ago is what it is. When you say I should not have a problem what are you suggesting? You saying I should be able to add the second branch into the drain and add the sink and not have a problem?

 

[Cacher_Chick]

A 1-1/2" drain line works fine on a bathtub, so I will leave it up to you to decide.

 

[Cacher_Chick]

I will add that if you want to/need to increase the size of the line to meet the current code, cutting out a section of concrete is not such a terrible thing. Much depends on how much needs to be cut.

 

[WJcandee]

If you're cutting the slab, just be sure you're not in an area that uses post-tensioning when building slabs. They were common when I was in Texas. Also Nevada and Southern California, and it can get pretty exciting if someone cuts an unbonded tendon. They are under more than 25,000 psi of tension, and if they are cut, the result can be pretty nasty as that energy is dissipated (and flying concrete can in some circumstances pose a life-safety issue). Also, the foundation can ultimately look like in this video I just found (although this tendon apparently failed on its own in a Rowlett, Texas, home without someone cutting it, or was never properly-tensioned).

[video=youtube;2kF4dXkPfJE]http://www.youtube.com/watch?v=2kF4dXkPfJE[/video]

 

[decarguy]

I don't think this slab is post-tensioned but I don't think the option of cutting into the slab is a real option for us. We'd probably go without a sink before we do that.